A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Other than writing an add-in to handle this sort of thing, the only way to do it is manually.
But another approach would be to allow enough room *above* the title placeholder for two lines, then set the placeholder's text box alignment to Bottom:
Select the text box
Rightclick, choose Format Shape
In the Format Shape dialog, click Text Box on the left
On the right, next to Vertical Alignment, choose Bottom.
This will cause the text box to grow UPWARD as more text is added, rather than downward, so it won't overwrite the subtitle text box.